The present invention generally relates to a process for satisfying the nutritional requirements of ruminants for methionine, and more specifically, to a process for meeting those nutritional requirements using the hydroxy analog of methionine (2-hydroxy-4(methylthio)butanoic acid) and its salts, amides and esters.
High producing dairy cows need methionine, lysine and other key essential amino acids to reach their genetic potential for milk production. While amino acids can be added directly to the diets of monogastric animals to overcome nutritional deficiencies, free amino acids are rapidly degraded by rumen bacteria and are of little or no practical benefit in alleviating amino acid deficiencies in ruminants.
Traditionally, undegradable intake protein (xe2x80x9cUIPxe2x80x9d) such as blood meal, fish meal, corn gluten meal and others have been used to provide essential amino acids to ruminants. It is difficult, however, to accurately deliver needed levels of methionine and other essential amino acids without providing excess levels of other non-essential amino acids and, any excess nitrogen which UIP delivers to the rumen must be degraded and eliminated by the animal. Consequently, formulating feeds which satisfy the methionine requirements using UIP sources is not only expensive, it can also affect cow health and productive status.
As an alternative to UIP, attempts have been made to modify or protect methionine in a manner so that it is not susceptible, or at least is less susceptible, to rumen degradation. Various xe2x80x9ccoatingsxe2x80x9d for methionine have been proposed which, in theory, enable the rumen protected methionine (xe2x80x9cRPMxe2x80x9d) to clear or xe2x80x9cbypassxe2x80x9d the rumen without significant destruction by rumen microflora and deliver this key amino acid to the small intestine. Once in the small intestine, the coating dissolves thereby freeing the methionine which is absorbed from the intestine.
The practical application of rumen protected methionine, however, has presented some challenges. For example, some products have limited solubility. For others, pelleting, expander conditioning, mixing, and other normal milling practices fracture the protective coating, making the methionine molecule vulnerable to rumen degradation. Some dairy producers have circumvented this problem by top dressing the rumen protected methionine on final rations. This labor intensive practice, however, does not allow the ingredient to be uniformly distributed in the diet. As a result, cows within a herd may consume different amounts of methionine.
It has been reported that the milk production of dairy cows can be increased by supplementing the diets of the cows with the hydroxy analog of methionine and its salts and esters. See, e.g., U.S. Pat. No. 4,388,327. Previous attempts to implement this technology, however, were met with unpredictable milk production responses.
More recently, the calcium salt and the free acid forms of the hydroxy analog of methionine have been combined with bypass fats in a dry product for use as an ingredient of a ruminant food ration. As understood, the level of inclusion of the bypass fat/hydroxy analog dry product has been determined using a computer model which matches the nutritional requirements of the ruminant with available feed ingredients. This approach, however, suffers from several disadvantages. Because the two ingredients are combined in a predetermined ratio, the product offers less flexibility in formulating a ration which meets a least cost objective and precludes the possibility of formulating a feed ration which includes the hydroxy analog of methionine but not bypass fat. In addition, the dry form of the product is susceptible to the formation of undesirable dust and to non-uniform mixing with other feed ration ingredients.
Among the objects of the invention, therefore, is the provision of a process for satisfying the nutritional requirements of ruminants for methionine, the provision of such a process in which it is unnecessary to coat or otherwise protect the methionine source from rumen microflora, the provision of such a process in which a predictable milk response is obtained, the provision of such a process which avoids providing excess levels of fats or other non-essential amino acids to the ruminant in order to satisfy the methionine needs, and the provision of such a process in which some of the UIP in a balanced ration may be replaced with a lower cost source of methionine to yield a cost improvement.
Briefly, therefore, the present invention is directed to a process for formulating a ruminant food ration for a ruminant. In this process, the methionine needs of the ruminant are determined. A plurality of natural or synthetic feed ingredients and the nutrient composition of each of said ingredients is identified wherein one of said ingredients is 2-hydroxy-4-(methylthio)butanoic acid or a salt, amide or ester thereof. From the identified feed ingredients, a ration is formulated to meet the determined methionine needs of the ruminant which comprises one or more grains, a hydroxy analog of methionine, and optionally a bypass fat wherein (i) the hydroxy analog of methionine is selected from the group consisting of 2-hydroxy-4-(methylthio)butanoic acid and the salts, amides and esters thereof, (ii) the hydroxy analog of methionine is added separately from any bypass fat which is included in the ration, and (iii) the ration is formulated on the basis that at least 20% of the hydroxy analog of methionine is assumed to be available for absorption by the ruminant.
Other objects and features of this invention will be in part apparent an d in part pointed out hereinafter.